PDA

View Full Version : swift 620 trying to kill itself


angus808
03-08-2010, 12:37 AM
I have a swift 620 that nearly beats itself to death before the RPMs get up. I noticed while assembling that the blade grips seemed too tight. It's been a while since I ordered the blades for it, but could the blades be too thick? Can this cause the seizures the swift goes through trying to get the lead/lag right in lower RPM range? I can move the blades back and forth, but it seems to me I need to use a little too much force to get them to move. I've got the bolt and nut just making contact with the blade grip.

birdDog
03-08-2010, 12:55 AM
I would see if I could file the blade thickness down a little.

angus808
03-08-2010, 01:22 AM
Probably what I need to do. Just measured the blades. 11.8 mm where the bolt goes through. Inside of the blade grips are 11.5 mm. Some of the blades the manual recommends are 12mm. ???

wzak29
05-10-2010, 02:30 AM
Sometimes blade grips can be a little to tight, just sand or file them down a little.

MaxAdventure
05-10-2010, 05:11 AM
I would not modify the blade nor the grip on that size heli. Get the right size blades for your grips. The bolt should go all the way through a nylon lock nut. Tighten the bolt enough that you can hold the heli on it's side and the blades will stay over the tail boom and over the canopy, but with a shake they will drop. if they don't drop, they're too tight. If they don't stay when you tilt the heli on the side, they're too loose.

be sure your main shaft is straight. Pull the shaft and roll it on a mirror, watch and listen for ANY irregularities.

be sure your fly bar is straight, same procedure.

be sure your feathering shaft is straight, same procedure.

check for slop on your head linkage.

Balance your blades, both should be the exact same weight and both should have the same center of mass.

Don't screw around with a 600mm heli, make sure you have the right parts and it's all balanced and assembled correctly. And don't run woodies over 1800RPM

rotorsport
10-31-2010, 05:59 AM
Did you solve the problem with the blade grips?

Charles

angus808
10-31-2010, 11:27 PM
It's been parked and stripped. I could never locate the problem. Everytime I tried something it would shake violently. Very frustrating. Have since built an Outrage 550 and a couple Trex machines. Smooth as glass, no problems. I'm thinking I bent or tweaked something, probably obvious, but was never able to isolate the problem. I changed parts, balanced rotor head, changed grips, checked shaft, etc. You could power up through the shake, problem was coming back down through it. Thats where the damage happened. Was like a cat getting hit by a car. Nothing to do but watch. I'm sure a more experienced builder would find the problem. I appreciate all the help.